| Rice is the main food crops in China,rice planthopper is a kind of pest which has a great effect on high and stable yield of rice.Currently,the control means mainly adopts an "attack" way by chemical control which killed planthoppers,so as to achieve the purpose of protection of rice.However,the long-term use of chemical pesticides not only destroyed the ecological balance,but also caused the pest resistance,and the pesticide residues in environment pollution problems.Therefore,we need to find a control method of rice planthopper that based on the "defense" strategy.This study used several natural materials as the main film-forming material,screened an piercing-sucking barrier film of a new,green,prevention and control of rice planthopper.Research the piercing-sucking barrier activity and the field test,and evaluate its safety in the paddy field environment.The main results are as follows:1.Five kinds of good film forming formulas have been screened out initially.Selected five better film formulations by determined its membrane solution viscosity,ductility and drawing degree,respectively is: formula 1: 12.5% rosin,10% colza oil,1.5% sodium alginate,7.5% peptone,2.5% emulsifier and 66%water;formula 2: 12.5% rosin,10% colza oil,1.5% sodium alginate,15%peptone,2.5% emulsifier,58.5% water;formula 3: 12.5% rosin,10% colza oil,2.25% sodium alginate,7.5% peptone,2.5% emulsifier,65.25% water;formula 4:5% soluble chitosan and 5% PVA-124,90% of the water;formula 5: 6.7% soluble chitosan,3.3% PVA-124 and 90% water.2.A piercing-sucking barrier film of brown planthopper has been optimizated.With rice seedling as test carrier,determinate the piercing-sucking barrier activity of five preliminary formulas,after 3 days,the brown planthopper correction mortality of the formula 3 and formula 5 is the highest(26.67%),the brown planthopper correction mortality of formula 4 is the lowest(17.24%);after 5 days,the brown planthopper correction mortality of formula 3 is the highest(46.43%),the brown planthopper correction mortality of formula 2 is the lowest(25%).By improving the membranous,ductility and corrosion resistance and optimized of formula 3,optimizated a piercing-sucking barrier film of brown planthopper.The formula is: 12.5% rosin,10% colza oil,3% sodium alginate,8% peptone,2.5%emulsifier,1% sodium benzoate,63% water.3.The piercing-sucking barrier activity of the piercing-sucking barrier film has been proved.Respectively,the rice seedling and tillering stage rice were used as the test carriers,measured the piercing-sucking barrier film is diluted 100 times has the best piercing-sucking barrier activity to brown planthopper,with the highest corrected mortality are 58.62% and 59.26%;the weight gain of the live insects are 0.11 mg and 0.14 mg,significantly lower than contrast which are 0.82 mg and0.84 mg;the live insects weight loss percentage are 86.59% and 83.91%;diluted25 times,50 times,200 times,400 times,brown planthopper correction mortality are 31.03%~55.17% and 33.33%~55.56%,the weight gain of the live insects are0.15~0.55 mg and 0.19~0.71 mg,the live insects weight loss percentage are32.93%~81.71% and 18.39%~78.16%,respectively,all these shows that the piercing-sucking barrier film has the piercing-sucking barrier activity.4.The physicochemical properties of the piercing-sucking barrier film of brown planthopper has been confirmed.The piercing-sucking barrier film’s p H range is6.34~6.91;viscosity range is 108~114 Pa·s;solid content is about 38.62%;the time of diluted to 25,50,100,200 and 400 times into membrane is about1.62~4.82 min;diluted to 25,50,100 times,measured the loss rate of its solid content is about 45.15~50.12% after indoor simulated rainfall,which showed that the film has certain rain erosion resistant ability.5.The effect of the piercing-sucking barrier film to rice seedling growth has been determined.Determined its high,fresh weight,dry weight and chlorophyll content after spraying the film on the rice.The result showed that,the height of the same day difference is the range of 1.1~2.5 cm,with no significant difference;the rice seedling fresh weight and dry weight of the same day difference respectively 0.0251~0.0892 g and 0.0018~0.0197 g,the contrast is the lowest when the maximum difference appeared;total chlorophyll content in the same day difference is the rang of 0.1868~0.4551 mg/g,with no significant difference.That proved that the film has no effect on the rice growth.6.The prevention and control effect of the piercing-sucking barrier film and its safety have been evaluated.The field test was conducted in Huangping County Jiuzhou town.The test shows that,the film diluted 50 times has better control effects,the average control effect is 64.21%.The mixture of the film diluted 50 times and Isoprocarb has the best control effect,the average control effect is71.7%,significantly higher than the Isoprocarb(64.04%)and the film’s control effect.Rosin acid is not detected in the soil and plants of rice,which indicated that the film is safe to the environment. |
